Singapore is approaching its yearly "haze" season, when smoke from forest clearing in Indonesia chokes the air, with this year likely to be worse than 2013's record pollution thanks to lack of action in Jakarta and an expected El Nino weather pattern.

The prosperous city-state, which prides itself on its clean air, was shrouded in heavy smog from slash-and-burn clearances on the neighboring Indonesian island of Sumatra last June which sent its air pollution index to a record high.

One year on, and an election-distracted government in Indonesia has still not ratified the Association of Southeast Asian Nations (ASEAN) 2002 Agreement on Transboundary Haze Pollution, and fires continue to burn in Sumatra.

That is despite outrage in Singapore as well as environmental groups putting pressure on Jakarta. Fires are used to clear land on plantations and can burn for weeks because of peat deposits below the surface.

There is also a growing likelihood of an El Nino weather pattern this year, meaning Singapore, as well as parts of Indonesia and Malaysia, could be set for months of intense haze with a knock-on effect on health and business, especially tourism.

"If we get four to six months of dry period in Southeast Asia starting from June, we could be in for a very difficult period, if companies' and people's behavior do not change," Singapore Environment Minister Vivian Balakrishnan told a conference.

Frustrated by the lack of progress, Singapore is taking matters into its own hands by proposing a new law that aims to punish individuals and companies outside its borders that are responsible for polluting its air.

That's expected to be tabled in parliament later this year. Legal experts hail the bill as a bold move, but question how it will be implemented.

Finding who is responsible for the haze is hard given the lack of evidence like maps showing who owns the land where fires are burning. Both Indonesia and Malaysia have refused to share clear and updated land use and concession maps so far.

"The basic evidential inquiry needed to resolve the problem - i.e. to find out who is setting fires to whose land - cannot even be conducted," said Alan Tan, professor at the Faculty of Law and Centre for International Law at the National University of Singapore. "Let alone the more complex tasks of actually prosecuting perpetrators or managing land use conflicts for the longer term."

Two of the world's largest palm oil companies - Wilmar International Ltd and Golden Agri-Resources Ltd - have been applauded for committing to no deforestation policies after criticism in the past.

Alongside the palm oil industry, paper and pulp companies have also been blamed for haze.

Indonesia's Riau province declared a state of emergency in February as haze from raging forest fires disrupted flights and marine navigation and tens of thousands fell sick with respiratory problems. The airport in the provincial capital closed for more than three weeks.

"The task force the president sent to the field was able to quench the fire but not solve the fundamental problem," Heru Prasetyo, head of Indonesia's REDD+ (Reducing Emissions from Deforestation and Degradation), told Reuters.